Add commenting directly to PDF / get a preview of the highlights page on the PDF

I annotate PDFs a lot. However, I have some issues:

1) It is annoying switching between the two PDF pages to make/view my notes.
2) Sometimes I want to make comments that aren’t attached to highlight but are attached to a certain page.

Potential solution:

Add a comment feature directly on the pdf (and have the notes also show up on the highlight page). This way you see a preview of the highlights page without having to switch; it would speed things up. This would also allow notes to be added without attaching them to a highlight but still linked to a page.

In addition, it would be helpful to be able to view the pdf and highlights at the same time which is already an issue. I think both would greatly enhance the pdf experience.

Mockups: